| 摘要 |
PURPOSE:To cast products of stable quality contg. no cavities and oxides efficiently by evacuating the inside of cavities by evacuation of the space in a molten metal vessel then pressurizing the space in the upper part of said vessel thereby casting the molten metal into the cavities. CONSTITUTION:After dies 12 are clamped, only the 2nd selector valve 20 is opened and the space 13 in the upper part of a molten metal vessel 6 is evacuated with a vacuum pump 17. The gas in cavities 15 flows through a stalk 7 and the inside of molten metal 14 according to the evacuation of the space 13 and is discharged as foam 24. The inside of the cavities 15 is evacuated. At this time, the surface 16 of the molten metal hardly changes. The 2nd selector valve 20 is closed, the 1st selector valve 18 is opened, and the space 13 is pressurized by a compressed air source 11, by which the molten metal 14 is flowed quickly into the cavities 15. This obviates the inclusion of air flow into the molten metal 14. After cooling for a suitable time, the valve 18 is closed, the valve 20 is opened to the atmosphere to restore atmospheric pressure in the vessel 6, the die 5 is opened, and the cast products are removed from the cavities 15. |
